This invention relates to crosslinked polymers, and in particular, to crosslinked polymers which form water-swellable, water-insoluble gels.
Linear polyalkylenepolyamines are rendered water-insoluble through the addition of diisocyanates at a temperature between about 30.degree. C. and about 200.degree. C., using techniques disclosed in U.S. Pat. No. 4,087,413. Unfortunately, the resulting water-insoluble products are prepared either in neat form or in the presence of a suitable solvent. Reactions of amines with diisocyanates are disclosed in U.S. Pat. No. 4,177,038. However, it is typically necessary to prepare such products under essentially anhydrous conditions because isocyanates moieties are hydrolyzed rapidly by water to yield substituted ureas.
In view of the fact that polymers such as acylated polyalkylenepolyamines are water-soluble, and in view of the fact that it would be highly desirable to render such polymers water-insoluble in an aqueous medium; it would be highly desirable to provide a process for preparing a crosslinked polyalkenepolyamine in a non-anhydrous environment.